There are many adventurers who are in the situation of having friends spread across many different Worlds, and cannot interact with them. There is also a housing shortage (which Patch 2.4 will try to address with more housing wards).
As a massive throng of adventurers begins making their plans to login exactly at 1:00am PDT to try to buy their houses, I would like to suggest a feature which could improve the experience for players in these situations.
Square Enix could provide the capability for players in one server to visit the housing wards of another server. To prevent gil from transferring between servers, trading would be disabled for visitors and only characters on the original server can receive permission to place items in houses. When visiting from another server, characters will have their server shown next to their name to differentiate them from others characters who are similarly named.
Understandably, creating Cross-World Housing involves technical challenges. However, seeing that Duty Finder and Frontlines already match players across servers in a single datacenter, the capability to send players from different servers into a single instance already exists and works admirably well.
Housing wards which can be accessed cross-world can begin with new housing areas, added in a future patch e.g. 3.0 Heavensward, and expanded to existing wards if appropriate.
I would be willing to pay real money to reward the development of this feature: something in the line of $4 per month in addition to the initial gil cost to buy the plot. The gil cost should be identical to existing plots so that housing remains a significant endgame accomplishment and the cash payment cannot replace the expenditure of in-game gil. Like many other players, I consider vanity items as a kind of an accomplishment and sale of vanity items feeling vaguely like pay to win. However, offering a paid option for existing content does not feel unfair.